Automatic regulation mechanism for timepieces



July 30, 1963 A. SPETZLER 3,099,129

AUTOMATIC REGULATION MECHANISM FOR TIMEPIECES 5 Sheets-Sheet 1 Filed 001;. 5. 1960 FIG. 1

FIG. 2 INVENTOR AUGUST L. SPETZLER Y FM W (3.1% Ma en ATTORNEYS July 30, 1963 A. 1.. SPETZLER 3,099,129

AUTOMATIC REGULATION MECHANISM FOR TIMEPIECES iNVENTOR AUGUST L. SPETZLER BY l M, I GM of f' ATTORNEYS lii AUTOMATIC REGULATION MECHANISM FOR TIMEPIECES Filed Oct. 5. 1960 3 Sheets-Sheet 3 INVENTOR AUGUST L. SPETZLER BY \5 e ami/7: 4

' ATTORNEYS United States Patent August lL. Spetzler, Peru, Ill, assignor to General Time Corporation, New York, NSiL, a corporation of Dera- Ware Filed Get. 5, 1950, Set. No. bflfiilll 13 Claims. (Cl. $-7l"i) My present invention relates to the automatic regulation of timepieces whereby the setting of the hands. automatically causes a change in the rate regulator. This invention relates especially to small timepieces, particularly to wrist watches, and the purpose of the invention is to provide an automatic regulator adjusting mechanism which involves the addition of a minimum number of parts to a standard watch movement, and which are so constructed and arranged that their presence does not increase the thickness of the watch.

In a conventional watch movement by axial shifting of the setting and winding stem, a setting pinion is movable into and out of engagement with the teeth of one of the wheels of the watch movement which is operatively connected with the hands so as to turn them whenever the setting stem is rotated.

In accordance with the invention a rate regulator adjusting member in the form of a gear segment is pivoted on one of the frame plates of the watch, preferably the front plate, and is arranged in the plane of the setting pinion, the teeth of this segment and those of the pinion being in spaced relationship. A coupling member is arranged bet-ween the regulator adjusting segment and the setting pinion. The coupling member has a working face at one side consisting of a single tooth which is engageable with the teeth of the segment, and on the opposite side a working face consisting of a series of teeth, that is, a few teeth or a small segment having a limited number of teeth, which are engageable with the teeth of the setting pinion.

When the setting pinion is in non-setting position both working faces of the coupling member are disengaged, or spaced away, from the corresponding cooperating mem bers, that is, the segment and the setting pinion. The coupling member is held in this position by means of a special supporting arrangement consisting in part of a pin projecting from the frame plate of the watch and a slot in the coupling member to cooperate therewith, this pin and slot arrangement being disposed near the first working face having the single tooth or finger. The other part of this special support is a flexible resilient support for the opposite face portion of the coupling member and, advantageously, consists of a spring finger which projects into a lateral recess in the coupling member.

This finger has a groove and symmetrical cam surfaces which engage a pointed projection extending into the recess from the portion of the coupling member which carries the series of teeth, and projects towards the slot previously mentioned. The spring finger is arranged to urge or bias the coupling member towards the setting pinion or in a direction to cause the bottom of the slot to engage and be held against the pin therein. The spring finger is preferably a long slender finger which is fixed at its opposite end to the frame plate. The special supporting device holds the coupling mem'ber in a floating position about midway between the segment and the setting pinion, and when the setting pinion is moved in the direction of the regular adjusting segment to the setting position, the pinion teeth engage the short series of teeth on the coupling member and then move this member against the tension of the flexible, resilient support and place the single tooth at the opposite face of the coupling member in engagement with the regulator segment.

With the parts in this setting position, by turning the 3,099,129 Patented July 30, 1963 ice stem and thereby turning the setting pinion, the coupling member is rocked in one direction or the other about its pivot pin and this causes the single tooth to move the regulator adjusting segment to change the adjustment of the rate regulator.

The arrangement is such that at the same time that the teeth of the setting pinion engage the limited series of teeth on the coupling member the setting pinion also engages a wheel of the watch movement which is operatively associated with the timepiece hands so that as the stem is turned, and thereby the setting pinion, the setting pinion simultaneously changes the setting of the hands and rock the coupling member as described.

The extent of the change in the regulator adjustment above-mentioned will be proportional to the change in the setting of the hands up to the point where the rocking of the coupling member brings the tooth at either end of the series into engagement with the teeth of the setting pinion. Should the turning of the setting stern be continued to bring about a larger change in the setting of the hands, the coupling member, that is, the last tooth mentioned will slide or click over the teeth of the setting member the flexing of the spring finger permitting this action.

Then when the hands have been set in either direction as far as desired, the setting stem will again be pushed in and this will result in returning the setting pinion to its original non-setting position. At the instant the last tooth of the coupling member is released from the teeth of the setting pinion the spring will cause the coupling member to be returned, that is, oscillated or rocked back to its original and normal position. Thus the return of the coupling member to its normal center position after a setting and regulator adjusting operation, does not cause a further change in the regulator.

In order to take full advantage of the invention the coupling member is pivoted on the shaft of the minute wheel of the watch movement, and the coupling member itself is arranged parallel with and lying against the surface of the minute wheel and, furthermore, when the parts are in the setting position the series of teeth on the setting member are positioned at the radius of the teeth of the minute wheel. Consequently, the minute wheel teeth and the coupling member teeth, being side by side, engage the same teeth of the setting pinion simultaneously. The segment portion of the rate regulator adjuster also lies against the face of the minute wheel. The thickness of the coupling member and the regulator segment are the same, and the combined thickness of these parts and the minute wheel is the same as the thickness of the setting pinion. Consequently the inclusion of the parts which compose the automatic regulating mechanism does not increase the thickness of the watch.

The invention will be further understood from a consideration of the accompanying drawings and description thereof which relate, by way of example, to a wristwatch.

In these drawings:

FIG. 1 is a view looking at the front plate of the watch with the dial removed;

FIG. 2 is a section taken on broken line 2-2 of FIG. 3;

FIG. 3 is a view similar to FIG. 1, but with parts shown in different positions;

FIG. 4 is a fragmentary view similar to FIG. 3, but with parts shown in still different positions;

FIG. 5 is a fragmentary section drawn to a larger scale and taken on line 5-5 of FIG. 3.

FIG. 6 is a similar section taken on broken line 66 of FIG. 1; and

FIG. 7 is a fragmentary view showing a portion of the back of the watch as indicated by the arrows 7-7 of FlG. 2.

Referring to these drawings, the frame of the watch comprises a front plate 10, and a rear plate 11 (FIG. 2)

interconnected by posts 12, i3 and 14 in a conventional manner. The watch has a dial 15 supported in any suitable manner.

The minute hand is indicated at 16 and is mounted on a sleeve shaft 17 at the inner end of which is the cannon pinion 13. The hour hand 1? is mounted on a second sleeve shaft 2-9 fixed to the inner end of which is the hour wheel 21. Cannon pinion 18 drives a minute wheel 22 and minute pinion 23 engages the teeth of hour wheel to drive it. Minute wheel 22 rotates on a stud shaft 2 which is fixed in an aperture in the front plate 1 The watch movement is entirely conventional and of this movement only the ratchet wheel 25, the center s1 aft 25 (FIG. 2) and center wheel 2'7 are shown. Associated with the ratchet Wheel 25 is a spring ratchet 28 to prevent rotation in the clockwise direction as viewed in the drawing. Rotation of ratchet wheel 25 winds the main spring of the watch. Center shaft 26 has a reduced extension 29 on which sleeve 1'7 of the cannon pinion rotates. Center wheel 27 drives or turns cannon pinion 18 through a conventional friction, or slip, drive in the form of a spring friction washer which is not visible. Such slip drive permits the hands to be turned in order to set them by rotating minute wheel 22 in a conventional manner.

The watch is also provided with a conventional winding or setting stern 3t} which is axially shiftable from a winding to a setting position, as will presently be described. At the inner end of setting stem there is a yoke member 31 which is pivoted to front frame in on a stud 32. Rotating on this stud is a yoke pinion 33 that is in constant mesh with a winding pinion 34 which rotates on a stud 35 fixed to the upper end of yoke 31, and also with a setting pinion 36 which rotates on a stud 3'7 fixed near the opposite end of yoke member 31. Also in constant engagement with the teeth of yoke pinion 33 is a pinion 38 which is mounted on the inner end portion of setting stem 36 which turns pinion 33, but is slideable therein when the stem is moved axially.

Axial movement of setting stem 36 causes yoke 31 to pivot about its supporting stud 32 and bring winding pinion 34 into engagement with the teeth of ratchet wheel 25 when the stem is pushed inwardly to winding position (FIG. 1). At the same time setting pinion 36 moves in the opposite direction to non-setting position. In the setting position (as shown in FIGURE 3) setting stem 30 has been pulled outwardly and setting pinion 36 is in engagement with the teeth of minute wheel 22 so that by turning the stem 36 the hands can be set.

The operative connection between setting stem 3t) which causes such rocking movement of yoke 31 comprises a shipper 3%, or short lever, which is pivoted at 40 to plate 10. A small pin 4-1 projects from its under side and engages a circular groove 42 formed in setting stem 3%}. At the opposite end of shipper 39 there is an outwardly projecting short stud 43 which is arranged to bear against the edge of yoke 31. Consequently, as the stem is pulled out from the winding position of FIGURES 1 and 2 to the setting position of FIGURE 3, the pressure of stud 43 against the edge of yoke 31 causes the yoke to swing about its pivot 32, and then stud 43 passes a shoulder 44 which locks the yoke in setting position.

It will remain so locked until stud 43 is disengaged from this shoulder by inward pressure on setting stem 30. Yoke 31, it should be explained, is biased or urged towards the winding and non-setting position of FIG- URE 1 by means of a scar type spring 45 which is coiled on post 13. One end of this spring is anchored at 46 to front plate It} and the opposite or free end of spring 45 is engaged in a groove on the inner end of setting pinion stud 37. For this purpose stud 37 is arranged to project through a slot 47 in front of plate ill as shown in dotted lines in FIGURES 1, 3, 4, and 5.

Fromthe description of the figures to this point the description relates to conventional watch construction.

Coming now to the mechanism for producing automatic regulation, tne rate regulator for the balance wheel is shown at 43 (see FlGURE 7 and is on the back of the watch. It is pivoted to rear frame 11 at 49 and provided with the usual element 5G for controlling the hair spring. in order to turn regulator 48 it is provided with a gear segment 51?, the teeth of which mesh with the teeth of another se ment 52- which is fixed to the rear end of a shart 53, this shaft extending to the front of the watch through post 12.

The rate regulator adjusting segment is shown at 54 and is an arcuate member which is formed integrally wit a flexible resilient supporting arm 55 having a hub portion 56 which is secured to the upper end of shaft 53 by means of a screw 57 (FIGURE 2). Consequently, when segment 54 is shifted or moved in either angular direction a change in the adjustment of regulator 48 is made through the coasting gear segments 52 and 51.

Referring now do FIGURE 1 where the parts are shown with the stem pushed inwardly to winding position, the winding pinion 34 is in engagement with ratchet wheel 25 and the setting pinion 36 has been moved outwardly to the right so that it is in its position of greatest separation from regulator adjusting segment 54. It is held in this position by means of spring 45 described above. The teeth of setting pinion 35 are also separated from the teeth of minute wheel 22 so the turning of stem 3b to Wind the watch will not change the setting of the hands.

Minute wheel 22 is a thin fiat metal gear as shown in FIGURES 2 and 5, and the regulator adjusting segment 54 is also a thin flat member and lies on the outer surface of front plate in beneath minute wheel 22, as also may be seen in FIGURE 5.

Referring again to FIGURE 1 the coupling member 58 is disposed in the space between setting pinion 3d and regulator adjusting segment 54. The coupling member is also a thin metallic member of the same thickness as re ulator adjusting segment 54-, and, like that member, also lies against the face of front plate 1% beneath minute wheel 22 (FIGURE 5). Coupling member 58 has at its right working face a short tooth segment consisting of a series of a few teeth 59, four teeth being shown, and adapted to engage the teeth of setting pinion 36.

On the opposite or left Working face of coupling member 53 there is a single tooth on which is adapted to engage the teeth of regulator adjusting segment 54 these teeth being advantageously of extremely small pitch much smaller than indicated in the drawings.

Coupling member 58 on one sidethe lower side as shown in the drawings has a large recess which, in effect, converts the member into the shape of an inverted U with enlargement at the bottom of its legs. Extending into the enlargement at the bottom of the left leg there is an open slot 61 within which the shaft 24 of minute Wheel 22 is received. Slot 61 and shaft 24 are, therefore, located near the single tooth 64).

On the interior of the opposite leg of coupling member 58 the enlargement terminates in an inwardly or lcft-Wardly pointed projection 62. A slender or rod-like spring member 63 projects into the recess in coupling member 58 and is provided with a groove 64 which reccives the point of projection 62. Spring 63 has an integral base portion 65 with an aperture which fits over a short pin 66 projecting from plate 10. A screw 67 passing through an aperture at the left of base 65 holds the members in fixed position.

By this construction the coupling member 58 is supported in a floating position intermediate the teeth of regulator adjusting segment 54 and those of setting pinion 36, the coupling member being supported in part by shaft 24 and in part by the spring finger 63. In this position the series of teeth 59 on the coupling member are located to the right of and out of line with the teeth of minute wheel 22 (FIGURE 1).

Referring now to FIGURE 3, the stem 30 is shown here as having been pulled out so that winding pinion 34 is disengaged from ratchet wheel 25 by the rocking of yoke 31, as previously described, and setting pinion 36 has been moved to the left. During this movement the setting pinion teeth first engage the series of teeth 59 on coupling member 58 and then move this member against the force of spring finger 63 toward the left, the slot 61 sliding along shaft 24 and bringing the single tooth on into engagement with the teeth of regulator adjusting segment 54. The teeth of setting pinion 36 also simultaneously engage the teeth of minute wheel 22.

When the stem 30 is turned the hands 16 and 19 will be se to any position desired, and simultaneously coupling member 58 will be rocked about shaft 24 as a pivot. Assuming that setting wheel 36 is rotated in the countercloclcwise directionthe right hand portion of the coupling member will be swung downwardly until the uppermost tooth of the short series of teeth 59 is engaged by the teeth of setting pinion 36. This may correspond, for example, to .a change of minutes in the setting of the hands.

The rocking of coupling member 58 causes the tooth 60 to move regulator adjusting segment 54 upwardly and thus make a change in the setting of regulator 48. Such change will be proportional to the extent of movement of the hands, up to the point where the last tooth, abovementioned, is engaged by the setting pinion teeth. After that the setting pinion can be turned toany extent desired so as to change the setting of the hands by more than 10 minutes and the uppermost tooth will merely slide or click over the teeth of the setting pinion without any further movement of coupling member 58 or adjustment of the regulator.

During the rocking movement of coupling member 58 the point 62 shifts along one of two cam-like surfaces provided on the lower and upper sides of groove 64 respectively. When stem B ll is pushed inwardly after completing the setting of the hands, setting pinion 36 will be returned to the non-setting position of FIGURE 1.

During this movement as soon as the setting teeth disengage the teeth 59 of the coupling member, the force of spring finger 63 operating through the cam-like surfaces above referred to on each side of groove 64 and cooperating carn-like surfaces provided on the upper and lower sides respectively of the pointed projection 62, will cause the coupling member 53 to be returned to its normal or center position as shown in FIGURE 1.

This position of the coupling member is determined by the alignment of shaft 24 and the groove 64 on spring finger 63 with respect to the center of stud 37 which supports the setting pinion, the parts being in non-setting position. The axis of coupling member 58, that is, the line joining single tooth 60 and the center of the series of teeth '59 is determined by the location of shaft 24- and groove 64 on spring finger 63. This emphasizes one of the important features of the invention, namely, that these two parts are so arranged that the axis of the coupling member is approximately parallel with the axis of setting stem 30. Consequently, the motion of the several parts including the setting pinion 36 and the coupling member 58, in shifting from nonsetting to setting position and vice-versa is not only all in one plane, but in a direction in such plane which is approximately parallel with the axis of setting stem 30.

It was mentioned previously that arm 55 which supports regulator adjusting segment 54 is flexible and resilient. The purpose of providing these qualities is the elimination of critical tolerances which would otherwise be required in the engagement of the coupling member with the segment 54 and with the teeth of setting pinion 36. In order to provide the resiliency and flexibility desired, arm 5'5 is made in form, as shown in FIGURES l, 3 and 4 with the legs of the 3 formation at right angle to the central radius of segment 54-.

It will be understood that with the construction of my improved automatic adjusting mechanism, above-described, relatively few parts are required in addition to the mechanism of a standard watch movement, inasmuch as the automatic setting mechanism utilizes the yoke 31 in bringing the parts of the automatic adjusting mechanism into operative connection, such yoke construction being a part of a standard watch movement. Furthermore, the automatic regulating mechanism is, in part, supported by the shaft of the minute wheel, another standard movement part. However, a very important feature of my improved mechanism is that by the disengagement of the coupling member 58 from both the setting pinion and the regulator adjustment segment the return of the coupling member to center position does not produce any change in the regulator adjustment. A further and quite important feature of the improved adjusting mechanism is the fact, as explained, that its presence does not in the least increase the thickness of the watch.

I claim:

1. In a timepiece, a movement including a frame plate, a rate regulator, hands driven by said movement, a setting stem axially shiftable between a winding and a setting position, a wheel operatively connected to turn said hands, a setting pinion and a rate regulator adjusting segment disposed in a common plane which is parallel to said plate, the setting pinion being translationally movable by said stem in said plane into and out of engagement with said wheel providing respectively a setting and a non'setting position for the setting pinion, a coupling member disposed between said setting pinion and said segment and in co-planar relation thereto, means for supporting said coupling member for pivoting and translation motion in the plane of said segment and setting pinion and biased towards said setting pinion, and a stop for limiting the translation motion of said member away from said segment as said setting pinion is moved to nonsetting position so that during said movement said coupling member is disengaged from both the regulating segment and the setting pinion.

Q. A timepiece as set forth in claim 1 wherein the regulator adjusting segment is supported on its pivot by an arm comprising a material which is flexible and resilient thereby eliminating critical tolerances in the engagement of said segment with said coupling member and said coupling member with said setting pinion.

3. A timepiece as set forth in claim 2 wherein the supporting arm for said regulator adjusting segment is of flexible resilient material and arranged in 8 formation at substantially right angles to the center radius of said segment.

4. A timepiece :as set forth in claim I wherein said coupling member has two points of support, and the plane joining these points is disposed in generally parallel relation to the axis of the setting stem.

5. In a timepiece, a movement including a frame plate, a rate regulator, hands driven by said movement, a setting stern axially shiftable between a winding and a setting position, a wheel operatively connected to turn said hands, a setting pinion and a rate regulator adjusting segment disposed in a common plane which is parallel to said plate, the setting pinion being translationally movable by said stem in said plane into and out of engagement with said wheel providing respectively a setting and a non-setting position for the setting pinion, a coupling member disposed between said setting pinion and said segment in coplanar relation thereto, means for supporting said coupling member for pivoting and translation motion in the plane of said segment and setting pinion and normally in spaced relation to both said segment and said pinion and biased towards said setting pinion but movable towards said segment, the movement of said setting pinion from nonsetting position to said setting position thereby causing interengagernent of said pinion, said coupling member and said adjusting segment so that turning of said pinion during setting of the hands imparts movement to said regulator adjusting segment.

6. In a timepiece, a movement including a rate regulator, hands driven by said movement, a setting stem axially shiftable between a winding and a setting position, a wheel operatively connected to turn said hands, a setting pinion movable by said stem into and out of engagement with said wheel providing respectively a setting and a non-setting position for said pinion, a rate regulator adjusting segment arrangement in co-planar and spaced relation with respect to said setting pinion, a coupling member disposed between said setting pinion and said segment, said coupling member having two opposed working faces one to engage said setting pinion and the other to engage said segment and having a slot adjacent said last-mentioned working face, means for supporting said coupling member for pivoting and translation motion and normally in spaced relation to both said segment and said setting pinion comprising a fixed member within said slot whereby said coupling member is allowed to shift axially and to pivot about said member, and flexible, resilient means for biasing said coupling member to a normal position with the end of said slot en aging said fixed member, the movement of said setting pinion from non-setting position to said setting position causing interengagement of said pinion, said coupling member and said adjusting segment so that turning of said pinion during setting of the hands imparts movement to said regulator adjustment segment.

7. A tirnepiece as set forth in claim 6 wherein said fixed member is the shaft of the minute wheel of said movement, and said regulator adjusting segment and said coupling member lie against the surface of said minute wheel.

8. In a timepiece, a movement including a rare regulator, hands driven by said movement, a setting stem axially shiftable between a winding and a setting portion, a wheel operatively connected to turn said hands, a setting pinion movable by said stem into and out of engagement with said wheel providing respectively a setting and a nonsetting position for said pinion, a rate regulator adjusting segment arranged in co-planar and spaced relation with respect to said setting pinion, a coupling member disposed between said setting pinion and said segment, said coupling member having two opposed working faces one to engage said setting pinion and the other to engage said segment and having a slot adjacent said last-mentioned working face, said coupling member also having a recess at right angles to said slot, means for supporting said coupling member for pivoting and translation motion and normally in spaced relation to both said segment and said setting pinion and with its axis disposed at a center position with respect to said setting pinion, said supporting means comprising a fixed member within said slot whereby said coupling member is allowed to shift axially and to pivot about said member, and a spring finger extending into said recess and engaging the side thereof opposite said slot and biasing said coupling member to said normal and center position with the end of said slot engaging said fixed member, the movement of said setting pinion from non-setting position to said setting position causing interengagement of said pinion, said coupling member and said adjusting segment so that turning of said pinion during setting of the hands caused rocking of said coupling memher away from said center position and imparts movement to said regulator adjustment segment.

9. A timepiece as set forth in claim 8 wherein cam surfaces are provided on said spring finger and on the surface of the slot in said coupling member, said cam surfaces coacting with one another when the coupling mem her is rocked away from said center position and serving to return said member to said position when the coupling member is released by movement of said setting pinion back to non-setting position.

10. in a timepiece, a-movement including a rate regulator, hands driven by said movement, a setting stem axially shiftable between a winding and a setting position, a regulator adjusting segment operatively connected with said regulator, a setting pinion spaced from and disposed in the plane or" said segment and moveablc by said stem in said plane between a setting and a non-setting position, said pinion at setting position engaging the teeth of a wheel operatively connected to turn said hands, a coupling member disposed between said spaced segment and setting pinion and having a single tooth engaging said segment and a series of teeth engaging said setting pinion when said pinion is in setting position, biasing means urging said coupling member towards said pinion, and a stop for holding the teeth of said member out of engagement with said pinion teeth when the setting pinion is in said non-setting position so that when said pinion is moved to non-setting position said coupling member will be disengaded from both said gear segment and said setting pinion.

11. A timepiece as set forth in claim 1 wherein the coupling member moves in a plane which is parallel with the axis of the setting stem.

12. A timepiece as set forth in claim 1 wherein the coupling member is disposed in side-to-side contact with the wheel which is operatively connected to turn the hands.

13. A timepiece as set forth in claim 5 wherein the coupling member and said wheel are positioned side-byside so that, during the movement of the setting pinion from non-setting to setting position, the engagement of the setting pinion with the coupling member and with said wheel takes place simultaneously.

References Cited in the file of this patent UNITED STATES PATENTS 2,542,430 Rabinow Feb. 20, 1951 2,933,883 Giger Apr. 26, 1960 2,955,411 Libman Oct. 11, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,099,129 July 30, 1963 August L. Spetzler It is hereby certified that error appears in the above numbered patent requiring correction and the,

t the said Letters Patent should read as correc ted below Column 1, line 66, for "regular" read regulator column 4, line 67, for "members" read member column 7, line 36, for "rare" read rate line 87, for "portion" read position column 8, line 7, for "caused" read causes line 23, for "moveable read movable same column 8, line 36, for "disengaded" read disengaged Signed and sealed this 4th day of February 1964.

(SEAL) Attest:

EDWIN L. REYNOLDS ERNEST W. SWIDER Attesting Officer AC ti 3 Commissioner of Patents 

1. IN A TIMEPIECE, A MOVEMENT INCLUDING A FRAME PLATE, A RATE REGULATOR, HANDS DRIVEN BY SAID MOVEMENT , A SETTING STEM AXIALLY SHIFTABLE BETWEEN A WINDING AND SETTING POSITIONS A WHEEL OPERATIVELY CONNECTED TO TURN SAID HANDS, A SETTING PINION AND A RATE REGULATOR ADJUSTING SEGMENT DISPOSED IN A COMMON PLANE WHICH IS PARALLEL TO SAID PLATE, THE SETTING PINION BEING TRANSLATIONALLY MOVABLE BY SAID STEM IN SAID PLANE INTO AND OUT OF ENGAGEMENT WITH SAID WHEEL PROVIDING RESPECTIVELY A SETTIN AND A NON-SETTING PINION FOR THE SETTING PINION, A COUPLING MEMBER DISPOSED BETWEEN SAID SETTING PINION AND SAID SEGMENT AND IN CO-PLANAR RELATION THERETO, MEANS FOR SUPPORTING SAID COUPLING MEMBER FOR PIVOTIN AND TRANSLATION MOTION IN THE PLANE OF SAID SEGMENT AND SETTING PINION AND BIASED TOWARDS SAID SETTING PINION, AND A STOP FOR LIMITING THE TRANSLATION MOTION OF SAID MEMBER AWAY 